Conventionally, rubber gloves are widely used in domestic work, various industries such as the food industry and electronic component manufacturing, and medical care (in particular, for surgery). The rubber gloves are required to be free of pinholes, have good feel so as to provide ease of work, and not to break during work.
As the rubber gloves, those obtained by dip molding from a natural rubber latex are commonly used. However, there is a possibility that the natural rubber latex gloves might cause allergy in some users due to trace amounts of protein present in a rubber component and, therefore, gloves made of a synthetic rubber latex such as, for example, an acrylonitrile-butadiene copolymer latex, which are free of the above-mentioned possibility, have been proposed.
U.S. Pat. No. 2,880,189 discloses a composition for dip molding, the composition comprising a water-insoluble multivalent metal oxide and an acrylonitrile-butadiene copolymer latex modified with a specific carboxyl group neutralized with ammonia. Although a dip molding obtained from such a composition for dip molding has very little possibility of causing allergy, since there are many pinholes it is necessary to dispose of a considerable number of defective products by screening. Furthermore, the dip molding obtained from the composition for dip molding, which contains no sulfur, tends to have a low tensile stress at 300% elongation (good feel), but poor tensile strength (possibility of breaking during work).
WO 97/48765 discloses gloves that are dip-molded using a carboxyl-modified acrylonitrile-butadiene copolymer latex, ammonium casein, sulfur, and a vulcanization accelerator, and using no zinc oxide. Although such a dip molding has a comparatively low tensile stress at 300% elongation and excellent tensile strength, there are many pinholes.
In the production of a dip molding, in order to vulcanize a dip molding layer formed on the surface of a dip molding mold, the dip molding layer is usually subjected to a vulcanization step in which it is thermally treated at a temperature of 100° C. to 130° C. for about 30 minutes to about 1 hour. Such a thermal treatment requires a large amount of thermal energy, and there is therefore a desire for a more energy-efficient production method.